review on sunscreens and their efficacy in the prevention of skin cancers and melasma. Part I

Sunscreens have been used since 1928. At that time they were used to prevent sun burns mostly because of filtering ultraviolet [UV] B light, the major cause of sunburning and tanning. Over recent decades, the knowledge concerning other harmful effects of UVB on the skin and the role of UVA in skin damage has widely grow. In this article, evidence regarding the efficacy of sunscreen use in the prevention of skin cancers and melasma will be reviewed